Inhibition of dipeptidyl peptidase-IV (DP-IV), an enzyme that inactivates both glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide 1 (GLP-1), represents a novel approach to the treatment and prevention of Type 2 diabetes, also known as non-insulin dependent diabetes mellitus (NIDDM). The therapeutic potential of DP-IV inhibitors for the treatment of Type 2 diabetes has been reviewed: C. F. Deacon and J. J. Hoist, “Dipeptidyl peptidase IV inhibition as an approach to the treatment and prevention of Type 2 diabetes: a historical perspective,” Biochem. Biophys. Res. Commun., 294: 1-4 (2000); K. Augustyns, et al., “Dipeptidyl peptidase IV inhibitors as new therapeutic agents for the treatment of Type 2 diabetes,” Expert. Opin. Ther. Patents, 13: 499-510 (2003); D. J. Drucker, “Therapeutic potential of dipeptidyl peptidase IV inhibitors for the treatment of Type 2 diabetes,” Expert Opin. Investig. Drugs, 12: 87-100 (2003); and M. A. Nauck et al., “Incretins and Their Analogues as New Antidiabetic Drugs,” Drug News Perspect., 16: 413-422 (2003).
WO 2010/056708 (published 20 May 2010), assigned to Merck & Co., describes a class of aminotetrahydropyrans, which are potent inhibitors of DP-IV and therefore useful for the treatment of Type 2 diabetes. Specifically disclosed in WO 2010/056708 is (2R,3S,5R)-2-(2,5-Difluorophenyl)-5-[2-(methylsulfonyl)-2,6-dihydropyrrolo[3,4-c]pyrazol-5(4H)-yl]tetrahydro-2H-pyran-3-amine.
However, the applicants have now discovered novel crystalline forms of (2R,3S,5R)-2-(2,5-Difluorophenyl)-5-[2-(methylsulfonyl)-2,6-dihydropyrrolo[3,4-c]pyrazol-5(4H)-yl]tetrahydro-2H-pyran-3-amine (Compound I).